[ADAM-326] Adding a 5-second retry on the HttpRangedByteAccess test.

The AMPLab webserver that is used in the test occasionally hangs?  If so, we catch
the HttpHostConnectException that the Apache lib throws, wait five seconds, and try
once more.
Merge pull request #328 from genomebridge/adam-326

[ADAM-326] Adding a 5-second retry on the HttpRangedByteAccess test.